<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Ajax jquery</title>
    <script src="jquery-2.1.3.min.js"></script>
    <script>
        $(document).ready(function () {
            $("#send").click(function () {
                var formData = $("#form1").serialize();
                $.ajax({
                    url:"file.php",
                    type:"POST",
                    data:formData,
                    success: function (responce) {
                        $("#response").html(responce)
                    }
                })
            })
        })
    </script>
</head>
<body>
<a href="index.php">MAIN</a>
<form id="form1" action="file.php" method="post">
    <div>a = <input id="a" type="text" name="a"></div>
    <div>b = <input id="b" type="text" name="b"></div>
    <div>c = <input id="c" type="text" name="c"></div>
    <div><input id="send" type="button" value="Send"></div>
</form>
<div id="response">
</div>
</body>
</html>